1. Description of the Prior Art
The present invention relates to a hinged attachment for helmet visors that can be operated by one hand only, enabling the visor to be tilted or swung with respect to the helmet in a motion where it goes from a position where it is turned down over the face to a raised position uncovering the face and, conversely, in a complicated movement that starts by a translation that moves the visor away from the helmet in order to release it from a joint or shoulder if any and that continues up to a raised position by a rotation that retracts the visor above the face.
Visor-fitted helmets are used to protect a pilot's head in the event of impact. The helmet protects the cranium while the visor protects the face and provides visual comfort in an aggressive environment: for example an environment with wind, dust, light, fog, etc. It also, if necessary, provides protection in a chemically aggressive environment. In the latter case, there needs to be tight sealing between the shell of the helmet and the visor in its turned-down position. This requires the presence of a peripheral joint and makes it necessary for the visor to meet the helmet frontally causing the visor to have a swinging motion that is not limited to a simple rotation and that can no longer be obtained by direct handling of the visor because such handling would require the pilot to perform a complicated movement requiring both hands.
Furthermore, certain helmets are fitted with a helmet mounted display that is an optical image projection system using a semi-reflective zone of the visor in the turned-down position to display piloting assistance symbols before the pilot's eyes. This requires very precise settings and excellent reproducibility of the position of the visor with respect to the other optical elements borne by the helmet.
2. Description of the Prior Art
There is a known way, described in the European patent application No. EP-A 88344, for making hinges that give the visor of a helmet a complex swinging motion that starts, in the turned-down position, with a translation that moves the visor away from the helmet, in order to release it from a shoulder, and continues up to a raised position by a rotation that retracts the visor above the face. However, these hinges need to be actuated by individual electrical motors. This makes them bulky and requires the helmet to be fitted with a battery that makes it heavy and complicates its maintenance.